Lecture 4 Flashcards
Types of Synapses?
-Electrical Synapse
-Chemical Synapse
Electrical Synapse?
Communication via the direct electrical coupling of 2 cells through gap junctions
Chemical Synapse?
Communication through the release and binding of neurotransmitters
Electrical Synapsis - Gap Junctions?
-Several connexions make up one connexon
-2 connexons combine to make a gap junction
Electrical Synapsis - Gap Junctions (PRO)?
Rapid Signal Transmission
Electrical Synapsis - Gap Junctions (CON)?
Postsynaptic Signal = Presynaptic Signal
Chemical Synapsis - Neurotransmitters Types?
1) Acetylcholine
2) Amino Acids
3) Purines
4) Biogenic Amines
5) Gases (NO, CO)
6) Peptides (much larger)
Chemical Synapsis - Neurotransmitters (PRO)?
Postsynaptic signal differs from presynaptic signal
Chemical Synapsis - Neurotransmitters (CON)?
Slow signal transmission
Chemical Synapsis - Neurotransmitters (CON)?
Slow signal transmission
Amino Acid Neurotransmitters?
-Inhibitory
-Excitatory
Inhibitory?
1) GABA
2) Glycine
(Primarily responsible for IPSP’s (Influx of Cl- ions and/or efflux of K+ ions))
Excitatory?
1) Glutamate
2) Acetylcholine
3) Catecholamines (Epi, NE, Dopamine)
4) Serotonin
5) Histamine
6) Aspartate
(Primarily responsible for EPSP’s (Influx of Ca2+))
Tyrosine is the precursor for?
Dopamine, Epinephrine, and Norepinephrine
Histidine is the precursor for?
Histamine
Tryptophan is the precursor for?
Serotonin
Life Cycle of Neurotransmitter?
1) Synthesis
2) Packaging/Transport
3) Docking (Priming)
4) Fusion and Release (Exocytosis)
5) Budding (Endocytosis)
6) Binding
7) Inactivation (Removal)
Small Molecule Transmitters are synthesized in?
Pre-Synaptic Terminal and stored in Clear Core Vesicles
Large Pro-Peptide Transmitters are synthesized in?
Cell Body and stored in Dense Core Vesicles
Clathrin?
Coats membrane and begins process of endocytosis (fuse with membrane and like a claw, lift it up and bring it back into presynaptic terminal and cleave it off)
Dynamin?
“Molecular Scissor” which pinches vesicle off membrane
Neurotransmitters binds to the postsynaptic receptor and alters?
Postsynaptic membrane potential
Neurotransmitters binds to the postsynaptic receptor and alters?
Postsynaptic membrane potential
Inactivation Methods?
1) Diffusion of the transmitter from the synaptic space
2) Cleaving the transmitter into inactive constituents
3) Reuptake of transmitter back into presynaptic neuron via transporters
Neuromuscular Junction?
1) Voluntary neuronal stimulus from CNS
2) AP leads to alpha-motor neuron stimulation
3) Ash released at postsynaptic membrane in neuromuscular junction
Myasthenia Gravis?
Autoimmune disease, where auto-antibodies target nAChR on the postsynaptic membrane (target nAChR and make ACh have nothing to bind to and doesn’t open channel so no contraction)
Myasthenia Gravis Symptoms?
1) Muscle Weakness
2) Drooping Eyelids
3) Fatigue
Myasthenia Gravis Treatment?
1) Acetylcholinesterase inhibitors